RXTE ASM 2010 Update

The RXTE ASM color and lightcurve data have been updated, as of
September 14, 2010.

The primary change in the revised data set is the stripping
away of more than 12,300 time-isolated spikes caused by a solar
glare problem.

Recent user inquiries about these spikes led to data study and
additional filtering criteria that have now been applied for these FITS
files and for all future data selections. The new filter (5 sigma
detection in A-channel && fitted A count rate > sum-band count rate)
supplements the other filters that we use, and it flags a spectral shape
never seen in real X-ray sources.

The 12,300 bad events represent a very small portion of the
total archive of 39.4 M measurements, but they are false and can cause
problems for users.

These steps do not entirely eliminate spikes in "dead" (off) sources
since there are systematic problems that are not affected by the new
(plus old) filter(s), e.g., flux sharing from bright sources, and some
soft spikes that are not strong enough to definitively separate them
from the extreme range of real X-ray sources. However, more than half
of the isolated spikes in our sample of 45 "dead" sources have just
been eliminated, with no impact on persistent bright sources, and so
this change has some value.

In addition, the new FITS masters provide mission-long
light curves for the newest (2010) requested additions to the
ASM monitoring catalog, which is now up to 581 sources.

If you have a question about RXTE, please send email to one of our
help desks.

This page is maintained by the RXTE GOF and was last modified on
Wednesday, 24-Nov-2010 16:23:42 EST.